Static laser speckle reduction method combining multimode optical waveguide and diffractive optical device

Abstract

The invention provides a static laser speckle reduction method combining a multimode optical waveguide and a diffractive optical device. The method comprises the following steps that Step 1, a laser beam is collimated and then input into the diffractive optical device, the diffractive optical device outputs the incident collimated laser beam as diffraction beams with different diffraction orders;Step 2, the diffraction beams with the different diffraction orders are focused by a lens, the focused beams are input into the multimode optical waveguide, the multimode optical waveguide modulates the transmission delay of different diffracted beams, so that the diffraction beams of all diffraction orders are output from the multimode optical waveguide at the delay difference delta T; Step 3, the diffraction beams output at different delays are collected by an imaging lens and imaged on a projection screen, the projection screen is provided with a rough surface, an image on the projection screen is received and processed by a digital camera, and the static laser speckle suppression is achieved. The static laser speckle reduction method combining the multimode optical waveguide and the diffractive optical device has the advantages that the reliability is high, electric energy supply is not needed, the response time is short, no mechanical running mechanism is needed, the system is simple, the size is small, and the cost is low.

Description

technical field [0001] The invention belongs to the field of laser display projection, and in particular relates to a fully static space / time hybrid laser speckle suppression method combined with a multimode optical waveguide and a diffractive optical device. Background technique [0002] Laser projection display system is getting more and more attention and welcome because of its rich colors, high picture quality, long life, high reliability, high efficiency, low energy consumption and other advantages. However, since laser light is highly coherent light, it will inevitably produce a picture noise called laser speckle. Laser speckle is formed by random coherent superposition of signals, which seriously affects the quality of the image. In the field of laser projection display, speckle will degrade the image quality of projection display, cause viewers to experience symptoms such as fatigue and dizziness, seriously affect the experience of laser projector users, and is the c...

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Problems solved by technology

[0004] In order to overcome the shortcomings of the prior art, such as insufficient speckle suppression effect, poor reliability, complex system, slow response time, need for power supply, large size, and high cost, the present invention provides a high reliability, no need for power supply, and fast response time. , no mechanical operating mechanism, simple system, small size, and low cost static laser speckle suppression method combined with multi-mode optical waveguide and diffractive optical device, using diffractive optical device to form diffracted beams at different angles, using multi-mode optical waveguide for different Time-delay modulation of the diffracted beam to achieve the purpose of reducing spatial and temporal coherence at the same time

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